1. Field of the Invention
The present invention relates to hearing aids. More specifically the invention relates to a hearing aid with suppression of wind noise.
In the context of the present disclosure, a hearing aid system should be understood as a system for alleviating the hearing loss of a hearing-impaired user. A hearing aid system may be monaural and comprise only one hearing aid or be binaural and comprise two hearing aids.
In the context of the present disclosure, a hearing aid should be understood as a small, microelectronic device designed to be worn behind or in a human ear of a hearing-impaired user. A hearing aid comprises one or more microphones, a microelectronic circuit comprising a signal processor, and an acoustic output transducer. The signal processor is preferably a digital signal processor. The hearing aid is enclosed in a casing suitable for fitting behind or in a human ear.
Several different types of hearing aids exist. One example is Behind-The-Ear (BTE) hearing aids. BTE hearing aids are worn behind the ear. To be more precise a housing containing the major electronics parts is worn behind the ear. An earplug or earpiece for emitting sound to the hearing aid user is worn in the ear, e.g. in the ear canal. In a traditional BTE hearing aid, a sound tube is used because the output transducer, which in hearing aid terminology is normally referred to as the receiver, is located in the housing of the electronics unit. In some modern types of hearing aids a conducting member comprising electrical conductors is used, because the receiver is placed in the earplug in the ear.
In the present context wind noise is defined as the result of pressure fluctuations at the hearing aid microphones due to turbulent airflow. As opposed hereto, acoustic sounds created by winds are not considered as wind noise here, because such sounds are part of the natural environment.
Wind noise in hearing devices is a severe problem. Wind noise may reach magnitudes of 100 dB Sound Pressure Level (SPL) and even more. Users of hearing devices therefore often switch their device off in windy conditions, because acoustical perception with the hearing device in windy surroundings may become worse than without the hearing device.
Depending upon wind speed, direction of the wind with respect to the device, hair length of the individual, mechanical obstructions like hats and other factors, magnitude and spectral content of wind noise vary significantly. With respect to noise, effects and causes reference is made to H. Dillon et al., “The sources of wind noise in hearing aids”, IHCON 2000, as well as to I. Roe et al., “Wind noise in hearing aids: Causes and effects”, submitted to the Journal of the Acoustical Society of America.
2. The Prior Art
It has been suggested to counteract wind noise by mechanical constructional measures, but these are generally too big or too bulky for implementation in a hearing aid.
In addition such approaches often lead to increased acoustic attenuation of the desired sound.
It is therefore a feature of the present invention to overcome at least these drawbacks and provide a hearing aid with improved wind noise suppression.